Stack up slipper pump and compact valve assembly



Sept. 20, 1966 H. M. CLARK ETAL STACK UP SLIPPER PUMP AND COMPACT VALVE ASSEMBLY 5 Sheets-Sheet 1 Filed Dec. 26, 1365 52 14 $69 23 54 INVENTORS Claw/6 rain/2a;

V w 7 i Q www a P 1966 H. M. CLARK ETAL 3,273,503

STACK UP SLIPPER PUMP AND COMPACT VALVE ASSEMBLY Filed Dec. 26, 1963 5 Sheets-Sheet 2 TOR5 fizzber M 2 2k 6211761 12 17. Brute 12a;

Va; fill/1 ATTORNEYS Sept. 20, 1966 H. M. CLARK ETAL 3,273,503

STACK UP SLIPPER PUMP AND COMPACT VALVE ASSEMBLY Filed Dec. 26, 1963 3 Sheets-Sheet 5 14 -$it3gj 5 15 r 5 i 17 L 71 Z5) INVENTOR5 Habez M Q'Zarft 6y QZ ZJGGJP ffflrzzalzazs www 1 TTORNE YS United States Patent 3,273,503 STACK UF SUPPER PUMP AND QGMI'ACT VALVE ASSEMBLY Hubert M. Clark, Bloomfield Township, Oakland Eounty,

and Gilbert H. Drutchas, Birmingham, Mich, assignors to TRW Inc, a corporation of Ohio Filed Dec. 26, 1963, Ser. No. 333,763 9 Claims. (Cl. 103-42) The present disclosure constitutes a continuation-inpart of our copending application Serial No. 280,947, filed May 16, 1963, now Patent No. 3,200,752.

This invention relates generally to pumps and more particularly relates to a so-called slipper-type pump utilizing a peripherally notched rotor carrying slippers which are free to move radially and rock angularly in following the cylinder wall of a pumping chamber and wherein the pump is particularly characterized by a stack up of parts including a pumping element cartridge having a ring-shaped member which not only has formed therein a cylinder wall to provide a pumping chamber, but which also includes a flow control valve which is not only balanced by flow on both sides thereof, but is so positioned as to reduce the overall pump length and thereby facilitate use of the stack up pump in a confined operating environment.

It is an object of the present invention to provide a pump construction characterized by a stack up of parts wherein sealing, accomplished by surface-to-surface face seals is actuated by pump-generated pressure to squeeze the parts of a cartridge assembly together and wherein the cartridge assembly can be maintained of a reduced axial length by arranging a flow control valve in a ring-shaped part forming the pumping chamber of the pump.

Another object of the present invention is to provide a pump with an integral flow valve construction wherein the valve is balanced by flow on both sides of the valve.

Yet another object of the present invention is to provide a pump construction wherein discharge fittings can be disposed radially, thereby facilitating installation.

A specific object of the present invention is to provide a valve assembly which is incorporated integrally in a ring-shaped part formed as part of the pump cartridge so that the resulting valve assembly can be tested separately, thereby removing the necessity of scrapping the whole pump housing in the event of a fault in the valve bore.

Another object of the present invention is to provide a pump construction wherein initial pressurization of a parts stack up is provided by a leaf spring and wherein the parts are held together without additional fasteners by pump-generated pressure during operation.

Many other features, advantages and additional objects of the present invention will become manifest to those versed in the art upon making reference to the detailed description which follows and the accompanying sheets of drawings in which a preferred structural embodiment of a pump incorporating the principles of the present invention is shown by way of illustrative example.

On the drawings:

FIGURE 1 is an end view of a pump provided in accordance with the principles of the present invention;

FIGURE 2 is a fragmentary cross-sectional view taken generally on line IIII of FIGURE 1;

FIGURE 3 is a cross-sectional view taken generally on line III-III of FIGURE 1;

FIGURE 4 is a reduced cross-sectional view taken generally on line IV-IV of FIGURE 3;

FIGURE 5 is an end elevational view looking at the side of the pump opposite FIGURE 1;

sired in connection with any special applications.

ice

FIGURE 6 is a fragmentary cross-sectional view taken on line VI-VI of FIGURE 5; and

FIGURE 7 is a fragmentary cross-sectional view taken on line VII-VII of FIGURE 5.

As shown on the drawings:

In the pump of the present invention, as will be evident from the description of the structural features incorporated, complete flexibility is afforded as may be de- However, for purposes of illustrating the principles of the present invention, a particularly useful application is made when the pump is incorporated in a hydraulic power assisting arrangement such as a power steering system of a dirigible vehicle. Thus it is contemplated that a power steering pump shown generally at 10 is provided and the pump has a can reservoir 11 formed with a filling spout 12 closed by a cap 13, thereby permitting the can reservoir 11 to be filled with a requisite supply of fluid.

As will be noted upon referring to FIGURES 2 and 3, the pump of the present invention is particularly characterized by a stack up of parts including in a longitudinal row a wear plate 14, a pumping element cartridge 16 and a pressure plate 17. The stack up of parts is then enclosed within a housing means which is shown as comprising a drawn steel shell 18 including an end wall 19, side walls 20 and a radially outwardly extending flange 21 suitably apertured as at 22 for connection in firm assembly with a relatively flat plate-like body member 23 having a fiat radial wall 24 and including a centrally disposed boss 26. To fabricate the shell 18, a plain blank of sheet stock is either drawn or stamped to provide the flanged cup-shaped configuration illustrated in the drawings and it will be understood that no further machining or finishing operations are effected.

In the formation of the steel shell 18, the inside surface of the side walls 20 is formed with a circumferentially extending shoulder 27, thereby to bottom a sealing member or gasket 28 against a peripheral shoulder 29 on the pressure plate 17. Thus, the interior of the drawn steel shell 18 is segregated into a high pressure zone D and a low pressure zone I.

Referring specifically to FIGURE 4, the pumping element cartridge 16 is shown in greater detail :and constitutes a generally ring-shaped member having an irregularly shaped axial bore forming a bore wall or cylinder wall 30 which is sized to have a substantial sealing relationship with a substantially circular rotor 31 at diametrically spaced lines of tangency indicated at L-L on opposite portions of FIGURE 4.

The tangent seal thus provided affords the utilization of a slipper-type pump with a reduced number of slipper elements and allows the rotor strength to be unimpaired. On opposite lateral sides of the points of tangency between the rotor 31 and the bore wall or cylinder wall 30, arcuate working chambers are formed and are indicated at 32 and 33, respectively.

The rotor 31 is a generally cy-lindrically shaped article which is particularly characterized by a plurality of notches shown generally at 34 and each specific notch includes a bottom wall 36 and substantially parallel side Walls each indicated at 37. In this particular embodiment, there are a total of eight notches 34. The bottom wall 36 is characterized by one or more recesses 38 in which is bottomed a coil spring 39 adapted to continuously bias a slipper element shown generally at 40 radially outwardly into sealing engagement with the adjoining cylinder wall or bore wall 3%.

In accordance with the principles of the present invention, the slippers are of a specific structural shape in that each slipper member is an elongated extrusion which in cross-section is somewhat circular, thereby to provide a curved inner wall 41 and an arcuate outer wall 42. Thus, the inner and outer walls 41 and 42 of each respective slipper 4t meet at points indicated at 43 and 44 which are actually formed on discrete radii.

Referring, first of all, to the inner wall 41, it will be noted that the diameter of curvature of the inner wall 41 is substantially equal to the width of a corresponding notch 46. The size of the slipper is controlled so that each slipper 40 -is free to move radially and to rock angularly with respect to the notch 34 and the rotor 31 in following the cont-our of the cylinder or bore wall 30.

Each arcuate surface 42 extending between the points 43 and 44 is of a curvature substantially the same as the curvature of the cylinder or bore wall 30, however, the curvature of the arcuate surface 42 is just slightly less than the curvature of the adjoining bore wall 30 in order to obtain the classic Kingsbury effect, namely, a film of oil is introduced under the leading edge of the slipper, thereby permitting the arcuate surface 42 to ride on a film of oil.

Extending longitudinally throughout the length of each entire slipper 40, is a centrally disposed recess 46 which has the effect of forming two positions of support on the arcuate surf-ace 42, or, in other words, two outboard areas. It has been discovered this particular form of slipper construction is especially efficient in a doublelobed pump construction, as illustrated herein, since the cam surface or cylinder wall or bore wall 30 is somewhat radical and because of the improved slipper characteristics, a good seal is maintained as the double support positions on the arcuate surface 42 engage the bore wall 30 and move through the transition areas between the points of tangent seal and the pumping chambers 32 and 33. Thus, the grooved slipper top surface is an important factor in stabilizing the overall rock condition and hop of the slipper 40 that is encountered in a double-lobed pump when pumping bore accelerations, radial and tangential, become high with the shortening of the intake to the working arc distance. The elimination of the center section throws the two positions of support on the two outboard areas and perm-its the slippers to retain the classic Kingsbury effect.

In order to maintain the same pressure condition under the slipper and in the bore cavity between two adjacent slippers under the transient pressure condition, the slipper is passing through in a 360 revolution, each slipper 40 is particularly characterized by a relief passage 47 formed in the inner surface 41 and extending from the point 44 far enough inwardly to intercommunicate the portions of the notch 34 inwardly of the slipper 48 with the Working chambers 32 and 33.

One of the side walls 37, 37 of each respective notch 34 is also characterized by a relief recess shown at 48, which recesses are provided for the purpose of maintaining substantially the same pressure under the slipper and in the tangent arc clearance cavity on the trailing side of the slipper after the slipper leaves the outlet port and enters the tangent arc. Thus each recess 48 functions as a timing notch and develops a relieving function as the slipper passes through the sealed area.

It will be noted that the ring 16 is particularly characterized by a pair of circumferent-ially spaced axial through openings 49 and 50 which are, for the purpose of forming passageways, intercommunicating ports in the wear plate 14 and the pressure plate 17. The ring 16 is further characterized by a pair of circumferentially spaced openings 51 and 52 through which extend a pair of dowel pins 53 and 54.

The outer peripheral surface of the ring 16 is particularly characterized by .a portion which projects radially outwardly at one side as at 56 in which are formed various passages and valve cavities in accordance with the principles of the present invention. At all points of the peripheral surface of the ring 16, it is spaced from the side walls 20 of the shell 18, thereby forming an annulus 57 around the ring 16, which annulus 57 is filled with pumping media, thereby to surround the pumping element cartridge 16 in such a manner as to muffle noise and insure quiet operation.

The structural characteristics of the wear plate 14 are also illustrated in FIGURES 2, 3 and 4 and it is significant to note that the wear plate 14 is characterized by a periphery which is recessed as at 60 and 61, thereby forming inlet areas which project radially inwardly to communicate with the inlet sides of the pumping chambers 33 and 32, respectively. The wear plate 14 is also provided with major and minor discharge ports 63 and 64 which communicate with the axial openings 49 and 50 in the ring 16.

The pressure plate 17 also has major and minor discharge ports indicated at 66 and 67. In referring to the ring member 16, one of the dowel pins 54 located in the opening 52, is shown illustrated in detail in FIGURE 2. Referring to that figure, it will be noted the pressure plate 17 is recessed as at 68 to receive the end of a corresponding dowel pin. Further, the wear plate 14 also has an opening 69 formed therein for each of the dowel pins and the housing flange 23 is also recessed as at 70 to receive the opposite end of a corresponding dowel pin, thereby retaining the parts against relative rotation.

The stack up of parts is also characterized by additional openings shown in FIGURE 7 wherein the pressure plate 17 is illustrated as including a restricted flow orifice 71 provided by a passageway which is counterbored as at 72, the counterbored section 72 opening into the discharge zone D.

The ring 16 has a passage 73 formed therein and the wear plate 14 has a passage 74. The housing flange 23 is recessed as at 76 and the recess 76 is intersected by an angled passage 77 counterbored as .at 78 to receive a fitting 79 and partially threaded at 80 so that a conduit may be connected thereto for carrying fluid at pump-generated discharge pressure to a point of utilization.

The wear plate 14 has formed therein a notch 81 which intersects the passage 74 and which communicates with a separate series of passages formed in the stack up of parts provided for housing a control valve assembly. In this regard, it will be noted that the housing flange 2 3 has an opening 82 threaded to receive a closure plug 83 bottoming one end of a coil spring 84. As shown in FIGURE 3, the coil spring extends through a corresponding passage 86 formed in the wear plate 14 and into a passage 87 formed in the ring 16. The pressure plate 17 has an opening 88 which is a slot, in actual effect, acting as a stop for the valve which comprises a valve member 89 including a pilot portion 90 which extends into the coils of the spring 84, thereby providing a shoulder 91 for bottoming the other end of the spring 84. The slotted passage 88 permits oil passage by the stem part of the valve extending therethrough into the opening 100, when the valve 89 is opened. The notch 81 communicates the discharge passage with the passages 82 and 86, thereby exposing the radial end of the valve member 89 to pump discharge pressure.

The opposite end of the valve 89 has an opening 91 formed therein which is closed by a closure plug 9 2, thereby providing an end face which is exposed to pressure in the pressure chamber D. The closure plug 92 bottoms a coil spring 93, the other end of which is engaged against aball valve 94 normally engaging a valve seat 96, thereby to regulate the flow of fluid through a passage 97.

The valve 89 is recessed at 99, thereby to provide a control land for regulating the intercommunication of the pressure chamber D with a pair of outwardly extending openings 101), 100, which openings 101), 1110 open into the annular inlet area I. Accordingly, if flow conditions are such as to actuate the valve 89 against the bias of the spring 84, fluid will be bypassed from the pressure chamllaer D into the openings 180, 100 and into the inlet zone In this regard, the ring member 16 is provided with a pair of angularly disposed aspirating passages 101, 101, each of which intersects a corresponding passage 100, 100, and angles downwardly in a convergent disposition so that the opposite ends of the aspirating passages 101, 101 lie in register with an opening 102 formed in the side walls 20 of the can-shaped member 18. The aspiration flow which results assists in keeping the inlet zone I filled with fluid to be acted upon by the pumping unit.

Referring to FIGURE 2, the pressure plate 17 is char acterized by a pair of spaced recesses 104, 104 which receive and seat the ends of a leaf spring 106. The ends of the spring 106 are reversely turned as at 107 to facilitate seating. The bowed central portion of the lea-f spring 106, indicated at 108, engages against a central embossment 109 formed in the wall 19, thereby continuously biasing the pressure plate 17 towards the body flange 23 and assisting in holding the stack up of parts in assembly with one another. The embossment 109 also receives on its opposite side a base member 110 carrying a threaded stud 111, the base member being fastened by a weldment shown at 112. The threaded stud i111 extends through a sealing gasket 1:13 and through an opening 114 in the can 11 so that a nut 116 can be turned on the threaded stud 111 to fasten the can 11 in firm assembly with the pump.

As shown in FIGURE 3, the housing flange 23 is recessed at 117 to receive and seat a sealing gasket 118 which engages and seals against the can 11 and against the flange 21. The cup-shaped housing means 18 is held in firm assembly with the housing 23 by means of a plurality of headed fasteners 119. Thus, a reservoir shown at R surrounds the pump unit. It will be understood that a nipple can be provided on the can for connection to a return line so that spent fluid may be returned to the reservoir from the point of utilization.

Referring specifically to FIGURES 2 and 3, it will be noted that the main body portion of the housing means, as Well as the boss 26, has formed therein an opening 120 for carrying a shaft bushing shown generally at 1 21 and characterized by a sleeve-like shell having a bearing liner 122 such as bronze or babbitt fused thereon. The shaft bushing 121 extends through the boss 26 and projects beyond the radial wall 24 formed on the main body portion 23 of the housing means. Thus, the shaft bushing 121 accomplishes a dual purpose in that the bushing 12*1 aligns a shaft 123 and also pilots the rotor 40 on its outer diameter, thereby eliminating the need for a separate sleeve which would normally be required to be pressed into the rotor 40. This feature eases manufacturing tolerances in aligning other internal parts of the pump.

The shaft 123 has a splined portion 126 connected to the rotor 40 at 127 and has an extension 12 8 which is piloted on the inner diameter of a recess formed in the pressure plate 17 and shown at 129, thereby easing manufacturing tolerances and decreasing noise. An end face 130 on the shaft 123 engages the center portion of the pressure plate 17, thereby permitting the pressure plate 17 to absorb thrust loads. The shaft 123 is retained in assembly with the rotor 40 of the pumping element cartridge by by means of a snap ring 131.

A shaft seal is shown generally at 132 and is contained in the end of the boss 26. The outer end of the shaft 123 may be connected to a driving source, for example, a pulley having a drive connection to the fan belt drive of an automotive engine.

As shown in FIGURE 6, any shaft leakage which occurs along the length of the shaft 123 is directed back to the inlet zone via a passage 136 extending from the portion of the boss 26 which contains the shaft seal 132 back to the reservoir R of the pump.

in operation, the outlet flow from the rotor 31, the cam insert or ring 16 and the slippers 40 which form the pumping element cartridge passes through the aligned ports and specifically the discharge ports 66 and 67 of the pressure plate 17 into the pressure zone D, whereupon the flow passes through the opening 72, the flow control orifice 71 and into the passageway 73, 74, 76, 177 to the discharge outlet 80. Pressures on opposite sides of the restricted flow orifice 71 are communicated to opposite sides of the flow control valve 89 by virtue of the pressure existing in the pressure chamber D and the pressure communicated via the notch 81 to the other end of the valve. Since the pressure differential caused by the flow control orifice 71 is referenced to the valve 89, the combination of the pressure differential and the flow control spring 84 provides a controlled output flow to the point of utilization which may consist of a power steering unit.

Excess flow is dumped as overflow relief into the bypass passages 100 in the ring member 116, which bypass passages are intersected by th aspirating passages 101, 101 in register with the make-up passage 102. There is thus produced an aspirator effect which insures filling the inlet areas of the inlet zone I with a sufficient supply of fluid. The combined make-up oil and bypass flow discharges into the annulus 57 to the inlet ports 60 and 61. There are also inlet ports 171, 171 similar to 60 and 61 (of plate 14) in the rotor side of plate 17, see FIGURES 1 and 2. Fluid at pump generated pressure acts on the pressure plate 17, thereby assisting in holding the stack up of parts together and eliminates the necessity for additional sealing means since the parts can be retained in face-to-f'ace sealing engagement with one another. In other words, as soon as the pump begins to operate and pump generated discharge pressure is communicated to the pressure chamber D, it will be evident that sealing, accomplished by surface-to-surface face seals, is actuated by the pressure in the pressure chamber D squeezing the parts of the cartridge assembly together, thereby minimizing the need for elastic scaling members to prevent leakage and bolts or other fasteners to hold the stack-up assembly together.

By virtue of the present arrangement, the stack up length of the pump is greatly shortened and the valve which is disposed at right angles to the stack up is extended through the ring member of the pumping cartridge, thereby eliminating the necessity of separate valve and spacer plates and affording a balanced flow valve and having a radial discharge fitting which is easy to install and which permits the pump to be advantageously exploited in areas where space requirements are at a premium.

Although various minor modifications might be suggested by those versed in the art, it should be understood that we wish to embody within the scope of the patent warranted hereon, all such modifications as reasonably and properly comes within the scope of our contribution to the art.

We claim as our invention:

1. In a pump,

a stack up of parts forming a pump cartridge and including a ring member having a bore forming a pump chamber and plate members forming surface face seals on opposite sides of said ring member all disposed in an axial row,

rotary fluid displacement means in said pumping chamber,

said stack up of parts having an axial through opening extending through said ring member spaced outwardly of said bore and disposed parallel to the axis of said bore,

casing means enclosing said stack up of parts and together therewith forming separated inlet and outlet zones,

means including said ring member forming a bypass passage,

said ring member having as a part of said by-pass passage a portion disposed transversely of and intersecting said through opening and extending outwardly therefrom in opposite direction to open into said inlet zone,

and a flow control valve in said axial through opening regulating the by-pass of fluid between said zones, whereby the valve is balanced by flow on both sides of the valve.

2. In a pump as defined in claim 1,

said ring member being further characterized by aspirating passage means formed therein intersecting said transverse portion of said bypass passage,

and reservoir means for containing a supply of liquid to be pumped, said casing means having a make-up opening for communicating liquid from said reservoir means into said aspirating passage means,

thereby to assist in keeping the inlet zone filled with liquid.

3. In a pump as defined in claim 1,

said rotary fluid displacement means being further characterized by a notched rotor journalled for rotation in said bore,

and slipper means in the notched portion of said rotor free to move radially and to rock angularly in following the bore wall of the ring member.

4. In a pump,

a flat plate like body member having a flat radial wall,

a stack up of parts including a ring part having a bore forming a pump chamber and plate members forming surface face seals on opposite sides of said ring part, all disposed in an axial row,

rotary fluid displacement means in said pump chamber,

said stack up of parts having an axial through opening extending through said ring part spaced outwardly of and generally parallel to the axis of said bore,

a flow control valve in said opening,

a cup-shaped can detachably connected to said flat radial Wall and enclosing said stack up of parts and together therewith forming separated inlet and outlet zones,

and means including said ring part forming a by-pass passage controlled by said valve for regulating the by-pass of fluid between said zones.

5. In a pump as defined in claim 4,

said axial through opening of said ring part having a pair of openings extending outwardly in opposite directions and to said inlet zone,

whereby said valve is balanced by flow on both sides of said valve.

whereby the stack up of parts is squeezed together into operative assembly without the need of additional fasteners.

7. A pump comprising a ring member formed with a cylinder wall prescribing a pumping chamber,

a rotor in said pumping chamber having peripheral notches formed therein,

slipper means in said peripheral notches free to move radially and rock angularly in following the cylinder wall upon rotation of the rotor,

a wear plate on one side of said ring,

a pressure plate on the other side of said ring,

said plates having inlet and outlet openings formed therein for communicating with said pumping chambers,

a cup-shaped enclosure including side walls spaced radially outwardly of said ring, said wear plate and said pressure plate and including an end Wall spaced axially from said pressure plate,

a sealing ring between said pressure plate and said side walls to segregate the interior of said cup-shaped enclosure member into a pressure zone adjacent said pressure plate and an inlet zone around said ring and said wear plate,

a housing member connected to said cup-shaped enclosure member and providing a radial wall abutting said wear plate,

and a shaft journalled in said housing and co-rotatably connected to said rotor for rotatably driving said rotor to move fluid from the inlet in said wear plate to said pressure zone, said pressure plate, said ring and said wear plate and said housing having an axially extending discharge passage formed therein and said housing having a radially directed outlet port formed therein for connection to a point of utilization,

and means forming a reservoir around said cup-shaped enclosure,

said cup-shaped enclosure having a make-up opening in communication with said inlet zone to supply pumping fluid to the inlet area,

said ring member having by-pass passages formed theresaid pressure plate and said ring member having a valve bore extending axially therethrough,

said valve bore having a valve axially movable therein to control the discharge of overflow excess from said discharge zone into said bypass passages and said discharge passage having a flow restricting orifice contained therein, the downstream side of said orifice being communicated to one side of said valve, thereby to control the operation of the valve as a function of flow.

8. A pump comprising three plate members comprising a first wear plate, a ring member and a pressure plate, all disposed in an axial row,

housing means comprising a cup-shaped member receiving said plate members and a housing flange closing the open end of said cup-shaped member,

a shaft journaled in said housing flange and having a peripherally notched rotor rotatable in said ring member, said rotor carrying slipper means in the peripherally notched portion free to move radially and rock angularly in following the cylinder wall of the ring member,

sealing means between said cup-shaped member and said pressure plate to divide the interior of the cupshaped member into a high pressure zone and an inlet zone,

said inlet zone surrounding said plate members and said high pressure zone being adjacent said pressure plate,

said pressure plate having an outlet port formed therein to discharge pump-generated pressure into said discharge zone,

said plate members and said housing flange having an axially extending discharge passage formed therein for conducting fluid from said discharge chamber to a point of utilization and a flow control valve extending axially through said plate members having one end thereof subject to the pressure in said discharge zone and having the opposite end thereof communicating with the pressure in said discharge passage,

said discharge passage having a flow orifice therein, whereby said flow control valve regulates the flow of fluid from said discharge zone to said inlet zone as a function of flow through the discharge passage.

9. A pump as defined in claim 8,

said cup-shaped member having a make-up opening formed therein,

one of said plate members having bypass passages controlled by said flow control valve and further including aspirating passages intersecting said bypass passages and opening adjacent said make-up passage to 9 10 induce an aspirating flow through said make-up pas- 3,009,420 11/ 1961 Livermore 10342 sage into said inlet zone, 3,099,964 8/ 1963 Eickmann 103-136 and means forming a reservoir surrounding said cup- 3,110,266 11/1963 Liverrnore 103136 shaped member and flooding said make-up opening 3,125,028 3/1964 Rohde 103-42 with fluid. 5 3,207,077 9/ 1965 Zeigler et a1. 103-42 References Cited by the Examiner MARK NEWMAN, Primary Examiner.

UNITED STATES ATE W. J. KRAUSS, Assistant Examiner. 2,599,927 6/1952 Livermore 103139 2,755,741 7/1956 Erskine 103-136 10 

1. IN A PUMP, A STACK UP OF PARTS FORMING A PUMP CARTRIDGE AND INCLUDING A RING MEMBER HAVING A BORE FORMING A PUMP CHAMBER AND PLATE MEMBERS FORMING SURFACE FACE SEALS ON OPPOSITE SIDES OF SAID RING MEMBER ALL DISPOSED IN AN AXIAL ROW, ROTARY FLUID DISPLACEMENT MEANS IN SAID PUMPING CHAMBER, SAID STACK UP OF PARTS HAVING AN AXIAL THROUGH OPENING EXTENDING THROUGH SAID RING MEMBER SPACED OUTWARDLY OF SAID BORE AND DISPOSED PARALLEL TO THE AXIS OF SAID BORE, CASING MEANS ENCLOSING SAID STACK UP OF PARTS AND TOGETHER THEREWITH FORMING SEPARATED INLET AND OUTLET ZONES, MEANS INCLUDING SAID RING MEMBER FORMING A BY-PASS PASSAGE, SAID RING MEMBER HAVING AS A PART OF SAID BY-PASS PASSAGE A PORTION DISPOSED TRANSVERSELY OF AND INTERSECTING SAID THROUGH OPENING AND EXTENDING OUTWARDLY THEREFROM IN OPPOSITE DIRECTION TO OPEN INTO SAID INLET ZONE, 